This invention relates to improved power slip mechanisms for facilitating the handling of well pipe.
During the drilling of a well, there are various situations in which it becomes desirable to temporarily support the weight of the drill string by a set of tapered slips received within a tapered slip bowl while an upper joint or stand of pipe, or a kelly, is being connected to or disconnected from the string. To speed the setting and release of such slips, there have been devised power slip units in which a number of slips have been power actuable upwardly and downwardly relative to a coacting slip bowl, to move the slips into and out of engagement with the tapering camming surface of the bowl. In some instances, the slip assembly has also been mounted to swing laterally to a location at a side of the well pipe when not in use. As examples, certain of the prior power slip arrangements are shown in U.S. Pat. Nos. 2,939,683, 3,210,821, 3,270,389 and 3,457,605.